A new study has found that Vitamin D supplementation might not provide as much cardiovascular protection as we thought.
Previous observational and prospective studies (that is, studies that look at what happens without trying to influence the outcome) have seen a link between low vitamin D levels and higher risk of cardiovascular events like heart attack, stroke, or other cardiovascular disease (heart disease) that may lead to death.
This recently published meta-analysis (a study that combines and analyses the results of several previous studies, providing stronger evidence) has found that vitamin D supplementation did not actually have any effect on cardiovascular disease risk.
It’s important to note that while this study did not show a link, that doesn’t necessarily mean that we are 100% certain one doesn’t exist. However, it may be that there is a different link between vitamin D levels and risk of heart disease. For example, much of our vitamin D is actually created in the body when the skin is exposed to sunlight. If you are regularly active, you’re likely to get outdoors more – even if it’s just walking from the car into the gym. Since small “doses” of sunlight (in most of Australia, 10-20 minutes per day is plenty) is enough to keep vitamin D levels normal, it might be that your activity or exercise levels are keeping your vitamin D high and your heart healthy (sunscreen blocks the body from creating vitamin D, so take that into consideration too). This is always the challenge with healthcare and health research – it’s difficult to completely control all possibilities!
What does this mean for you?
Unless you are taking vitamin D specifically for cardiovascular protection or heart health, without being told to by your doctor, this news probably won’t have much of an impact on you.
Of course, if you are taking vitamin D pills, tablets, or other supplements because your doctor or dietitian told you to, keep doing so! Vitamin D plays many roles in the body, including supporting immune function and musculoskeletal health. If you’re not sure whether you need to increase your vitamin D intake, speaking to your GP or a registered dietitian is your best bet. Of course, we all feel better and are more healthy with a bit of extra activity, so you can always take yourself outside!
For more information:
Australian Bureau of Statistics, Feature Article: Vitamin D https://www.abs.gov.au/ausstats/abs@.nsf/Lookup/4364.0.55.006Chapter2002011-12
National Institutes for Health, Fact Sheet for Health Professionals: Vitamin D https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
Barbarawi, M., Kheiri, B., Zayed, Y., Barbarawi, O., Dhillon, H., & Swaid, B. et al. (2019). Vitamin D Supplementation and Cardiovascular Disease Risks in More Than 83 000 Individuals in 21 Randomized Clinical Trials. JAMA Cardiology. doi: 10.1001/jamacardio.2019.1870